Basting stitch mechanism for household zigzag sewing machine

ABSTRACT

A zigzag sewing machine equipped with mechanism in which an eccentric is utilized in connection with the shuttle driving mechanism to vary cooperation of the shuttle with the needle for selectively preventing the interlocking of the first and second threads respectively carried by the needle and the shuttle, whereby a skip stitch may be obtained to provide a greatly spaced stitches likely to meet the requirement of basting stitches.

United States Patent Sawada 1 Oct. 10, 1972 [54] BASTING STITCHMECHANISM FOR [56] References Cited HOUSEHOLD ZIGZAG SEWING UNITED TPATENTS MACHINE 3 361 100 1/1968 Bo 112/159 no [721 Invent sawadaokazak" Japan 1,411,003 3/1922 De Voe ..112/154 73] Assignee; Aisinseiki Kabushiki Kaisha, 3,490,401 1/ 1970 Hamlett ..1 12/ 159 Kariya,Aichi Pref.,Japa n V Primary Examiner-Patnck D. Lawson [22] Filed: 16,1970 Att0mey--Pierce, Scheffler & Parker 21 A 1. N 98 632 l 1 pp 57ABSTRACT A zigzag sewing machine equipped with mechanism in v [30]Foreign Application Pnonty Dam which an eccentric is utilized inconnection with the Dec. 23, 1969 Japan ..44/ 1( 3 9 shuttle drivingmechanism to vary cooperation of the shuttle with the needle forselectively preventing the [52] US. Cl ..112/159 interlocking of thefirst and second threads respective- [51] Int. Cl. ..D05b 3/02 y a d ythe needle and th shuttl hereby a 53 skip stitch may be obtained toprovide a greatly Field of Search ..112/158 R, 159, 154

spaced stitches likely to meet the requirement of basting stitches.

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SHEET 3 0F 4 BASTING STITCH MECHANISM FOR HOUSEHOLD ZIGZAG SEWINGMACHINE BACKGROUND OF THE INVENTION mal thread concatenation may beprevented by utilizing various methods such as manipulation of thelooper or needle thread or by providing special needles, attachment inthe bed of the sewing machine or a mechanism which serves to interruptthe endwise reciprocation of the needle-bar at predetermined intervals.

Even though greatly spaced stitches may be produced for the bastingstitches, all of these methods complicate the construction as well asoperation of the sewing machine. Additionally, and often more serious,it requires considerable skill properly to set the related sewingmachine controls, these being the drawback of the prior art andundesirable to reduce the manufacturing cost of the sewing machine.

Generally speaking, the present invention contemplates the provision ofmechanism in which the interruption of the stitch formation is effectedby simple, conveniently accessible, and easily adjustable parts, andwhere such parts are capable of incorporation into sewing machines ofconventional type.

SUMMARY OF THE INVENTION The present invention comprises mechanism toinerrupt the cooperation of the loop taker shuttle with the needle atpredetermined intervals under the condition that the other sewingmachine controls are adjusted for zigzag sewing operation. Theinterrupting mechanism serves to prevent the hook of the loop takershuttle from cooperating with the needle, with the hook positioned infront of one of acting positions of the needle but at the back of theother. The mechanism is accompanied by means effective for selectivelyrendering the mechanism inoperative so that the sewing machine remainsin the normal zigzag or straight stitch sewing mode. The mechanism isincorporated into sewing machines of conventional type in which theshuttle alternately makes one-half backward and forward revolutionsabout an axis substantially perpendicular to an imaginal plane in whichlies the zigzag oscillation of the needle.

' The present invention eliminates the disadvantages of the prior artskip-stitch mechanisms briefly outlined above by placing a simple andcompact interrupting mechanism within unused space of the sewingmachine. According to the present invention, the stitch interruption maybe effected by a simple, conveniently accessible, and easily adjustablemechanism being capable .of incorporation into sewing machines ofconventional type.

It is an object of this invention to provide an improved stitchformation i nterrupting mechanism for a zigzag sewing machine atpredetermined intervals.

It is another object of this invention to provide a stitch formationinterrupting mechanism that is manually adjustable to render themechanism inoperative so that the sewing machine remains in the normalzigzag or straight stitch sewing mode.

Since the mechanism of the present invention is readily applicable tosewing machines of conventional type as above briefly outlined, thezigzag oscillating mechanism which they might have will not specificallybe illustrated and set forth here.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an elevational view of amachine embodying certain features of the invention, parts being brokenaway;

FIG. 2 is an enlarged detailed perspective view of the componentsparticularly showing the shuttle driving parts of the machineillustrated in FIG. 1;

FIG. 3 is the similar view to that of FIG. 2 but it shows the connectingrod and the lever of the bottom shaft in assembled condition;

FIG. 4 is the same view as that of FIG. 3 but it shows an explodedperspective view of the elements;

FIG. 5 is a diagrammatic view showing the relationship between theshuttle and the needle;

FIG. 6a to FIG. 7b are diagramatic showings of the resultant stitches inenlarged scale; and I FIG. 8 is a diagrammatic view showing theadjustment of the lever relative to the crank of the main drive shaft ofthe sewing machine.

DESCRIPTION OF THE PREFERED EMBODIMENT The present invention isillustrated in the drawing as embodied in a sewing machine having aconventional zigzag mechanism that is herein illustrated and describedonly insofar as it is believed to be necessary for an understanding ofthis invention.

With reference to the drawings, FIG. 1, such a sewing machine mayinclude a base 1 having the usual hollow upright bracket 2 extendingupwardly therefrom,

the hollow arm 3 extending, in substantially the usual manner, over base1 to present the usual front bearing upright 4 immediately over needleplate 5 provided base 1. Upright 4 may provide bores or other suitableguides in which may slide presser foot bar 6 and needle bar 7. In arm 3may be positioned a main drive shaft 8 (shown only in part, and dotted)from which, by suitable mechanism (not shown), reciprocating motion isimparted to needle bar 7. A combined pulley-and-hand wheel 9 is attachedto the main drive shaft 8 at the end thereof extending beyond bracket 2,and provides fro association therewith of a belt or other suitable meansfor driving the machine. Thread-carrying needle 10 receives a singlethread from any suitable spool or other source of supply through thenecessary tensions and feed pick-ups, which need not be specificallydesignated here. The needle 10 is reciprocated by the needle bar to passthrough a known opening (not shown) in presser foot 11 and known openingin the needle plate 5 to penetrate fabric (not shown) which may havebeen positioned upon the needle plate. The usual feed action by feeddogs (not shown) may be obtained from eccentrics, operating from maindrive shaft 8 through eccentrics l2 and 13 (shown only in part inFIG. 1) to actuate the usual bell cranks (not shown).

Suitably mounted on the under side of base], as for instance, in bearinglugs 14 and 15 is a bottom shaft 16. At the right end of the shaft 16 isfastened an arm or lever 17 which in turn is rotatively connectedthrough connecting rod 18 to crank 19 on the main drive shaft 8. Theshaft 16 carries at its left end a segment bevel gear 20 which mesheswith another bevel gear 21 carried by shaft 22 perpendicular to theshaft 16 in an imaginary plane substantially parallel to the base 1, asshown in FIG. 2. Atthe front end of the shaft 22 as viewed in FIG. 2 isfastened driver 23 of usual configuration engaging with known loop takershuttle 24 which is free to rotate within the usual circular race (notshown) one-half back and forward revolutions of about l80 to onecomplete revolution of the main drive shaft 8-The segment gear 20 isaccordingly only provided with enough teeth to rotate the driverone-half revolution of about 180. The needle bar 7 is mounted forreciprocation in needle barframe r holder 25, as indicated by the doublearrow a, said frame being in turn mounted for oscillation at rightangles to the work feeding direction about a fixed pivot or spindle 26-supported by the frame of the machine, as indicated by the double arrowb in the drawing. Reciprocation of the needle is effected'in a knownmanner by coupling of the, needle bar 7 with the main drive shaft 8 ofthe sewing machine via crank 29 and link 27 connected to journal pin 28affixed to the bar 7 just back of the bar frame 25,.Crank pin 29 is heldin fixed eccentric position through member 30 being in turn affixed toanother crank pin3l on the counter weight driving crank 26'. The numeral32 denotes the usual needle thread take up member driven by said othercrank pin 31. Linked to the needle bar 25 is one end of control bar 33whose opposite end is in turn linked to a reciprocating member of zigzagdrive mechanism which may have been assembled within the hollow arm 3.The numeral '41 denotes a control lever customarily used in the zigzagdrive mechanism for pre-setting the overstitch width. As previouslystated, the zigzag drive mechanism need not be specifically. illustratedbecause it may take any conventional type when applied to the mechanismof the present invention.

With reference to the skip-stitch mechanism of the present inventionshown in FIG. 2 to FIG. 8, the mechanism is shown more clearly inenlarged scale. The connecting rod 18 is at its lowermost end connectedto .the lever 17 through a pin generally shown by the referencecharacter 34 in FIG. 4. 'The pin 34. is longer than would ordinarily berequired. Section 34a of the pin fits the bearing 18a in theconnecting-rod 18 and the axially extending section 34b is eccentricwith the axis of the section 34a and fits through the bearing 17a in thelever or arm 17 as will be seen in FIG. 4. At the left-hand end of thepin, is carried a small pin 35 firmly fitted in radial hole 34c withboth ends slightly extended beyond the periphery of the section 34b, asshown in enlarged view of FIG. 3 and FIG. 4. On the end face of thebearing 17a of the lever 17 is formed two radially opposed notches 17badapted to receive said small pin 35, thus the notches lock with thesection 34b in a given side with respect to the center of thesection'34a. A coil spring 36 mounted on the pin 34 is disposed betweenthe bearing of the connecting rod 18 and knob 37. formed at the end ofthe pin normally to force the pin outwardly, this motion holding thesmall pin 35 in engagement with the notches 17b. If a displacement ofeccentric position of the section 34b is required with respect to thecenterof the section 34a, the small pin 35 is disengaged from thenotches merely by pushing the knob inwardly to the left in the bearings18a and 17a; the pin may then be turned by hand, the knob 37 beingknurled to provide a better grip. When the leftward pushing is released,the spring 36 immediately forces the small pin 35 backinto engagement,thus relocking the setting. The illustration in FIG. 3 shows the smallpin 35 in one of its engaged positions.

. In FIG. 5, the numeral 38 denotes the shuttle of known andconventional type ordinarily used in the popular household sewingmachines, which shuttle receives a bobbin or spool (not shown) having asecond thread wrapped thereon. The shuttle is free to rotate on aninternal surface of the known circular race shown by dot-and-dash lineand by numeral 39. The center of the race is substantially opposite astud 40 secured to and extending from the center point of the, shuttleand aligned with the axis of the driving shaft 22 (FIG. 2). Rotativelyand removably mounted on thestud 40 is the spool in the sewing operationto supply the second thread for interlocking with the first threadcarried by the needle. In FIG. 5, the shuttle is shown in its restposition just prior to start up of rotation. in the clockwise directionto take the loop having been formed inthe first thread carried andengaged by the eye of the needle. The shuttle first rotates in theclockwise direction about one-half revolution of and then rotates in thereverse direction the same angular amount, returning to its originalposition shown in heavy line in FIG. 5. The shuttle alternately repeatssuch forward and reverse rotations per one .revolution of 360 of themain drive shaft of the machine. The numerals 10a and 10b respectivelydenotes lowermost positions of the needle having reached extreme ends ofits downward travel respectively in two successive different zigzagsewing cycles. When the needle 10 carries thread engaged in its eye inusual manner through the fabric, and then is started on retraction, theslack thus produced in the thread forms a loop. The hook 38a of theshuttle 38, as the shuttle rotates to the clockwise direction as viewedin FIG. 5, is presentedimmediately beside the eye (not shown) of theneedle 10 and will engage within the loop thus produced.

At this stage of the operation, the shuttle receiving the second threadbobbin, passes through the loop and on retraction of the needle, theloop is drawn through the fabric, where the usual interlock of thesecond thread with the first thread follows in producing the usuallockstitches. I

As will be seen from the preceding, the hook 38a can catch the loop inevery sewing cycle regardless of whether the needle position is at 10aor 10b because the book may move past the eye in every sewing cycle.It'will be further noted that if the hook starts its loop taking motionto the right from the position 38a, after the position 10a but before10b, the stitch formation at the position 10a is prevented. This is veryimportant in obtaining the resultant stitches required.

As will be explained in detail below when the pin 34 is so adjusted byhand that the eccentric section 34b is displaced upwardly and held asshown in dotted line by the reference character 34b in FIG. 8, sewingmachine is placed in the skip-stitch mode, but when the section 34b ispositioned in the lowermost position as shown in heavy line by the thereference character 34b the sewing machine remains in the conventionalsewing mode.

By this adjustment, the oscillation of the lever 17 is varied as to itsposition from are B to are A as shown in FIG. 8.

Turning now to the operation of the presently disclosed invention, whenthe pin 34 is manually so adjusted and held that the hook 38aaccordingly starts its loop taking motion before the needles position a,the sewing machine operates in the conventional mannersewing zigzagstitches depending upon the setting of the other sewing machinecontrols. When, however, the pin 34 is so adjusted that it rotatesonehalf a revolution and section 34b is displaced to and maintained atthe position represented by the reference character 34b the hook 38aadvances its starting position to the position 38a as shown in dottedlines in FIG. 5. The stitch formation is thus prevented at the needlesposition 10a, that is, in every alternate cycle'of sewing straightstitches greatly spaced result even though the other sewing machinecontrols remain in zigzag sewing positions. The resultant stitchinterval is about twice that of the normal straight or zigzag stitchesas will be readily seen in FIG. 6b in contrast to FIG. 6a. In FIG. 6aand FIG. 6b, the small holes represent the needle holes in enlargedscale and the heavy line represents the thread laid on the surface ofthe fabric. In the stitches resulting from the skip stitch operationFIG. 6b, the needle holes in the left column are left disconnected withthe sewing thread and the required greatly spaced straight stitches thusresult.

When the other sewing machine controls are adjusted for the blind stitchoperation, while the pin 34 is maintained at the same skip stitchposition, further greatly spaced straight stitches may result as viewedin FIG. 7a and FIG. 7b. In the stitches of FIG. 7b, the distance betweenany two neighboring stitches is four times as long as the distance ofthe normal blind stitches in FIG. 7a. The desired straight stitches,greatly spaced, will thus be obtained for the basting stitches.

What is claimed is:

l. A sewing machine comprising a needle bar frame, a needle bar slidablycarried thereby, a needle mounted on said needle bar, means forreciprocating said needle bar vertically, means for oscillating saidneedle bar frame between two lateral positions at right angles to thework feeding direction, a shuttle means, means for oscillating saidshuttle means about its axis between two limits in a plane parallel tothe direction of oscillations of said needle bar frame to normallycooperate with said needle in each lateral position to form zigzagstitches and means for selectively moving the limits of oscillatorymovement of said oscillatable shuttle about the axis thereof so thatsaid shuttle will not pass said needle when at one of its lateralpositions whereby a basting stitch will be formed by said needle andsaid shuttle means at the other lateral position.

2. A sewing machine as claimed in claim 1 wherein said means for movingthe limits of oscillatory movement of said oscillatable shuttle includesa connecting rod mounted at one end to a crank provided on the maindrive shaft of the sewing machine, rotatably adjustable pin meansmounted at the other end of said connecting rod, a lever connected atone end to said adjustable pin means for. oscillation thereby, a shaftoscillatable by said lever, said shuttle means being operal connecgtedto said oscillatable shaft, said rotata y ad usta le pm means having aneccentric portion connected to said lever and means for selectivelyrotating said pin means so that the eccentric portion of said pin meanswill change the limits of oscillation of said shaft.

3. A sewing machine as claimed in claim 2 wherein said means forselectively rotating said pin means includes means for locking said pinmeans in a selected position.

4. A sewing machine as claimed in claim 3 wherein said adjustable pinmeans includes means for manually operating said locking means and foradjusting said pin means to the desired position.

1. A sewing machine comprising a needle bar frame, a needle bar slidablycarried thereby, a needle mounted on said needle bar, means forreciprocating said needle bar vertically, means for oscillating saidneedle bar frame between two lateral positions at right angles to thework feeding direction, a shuttle means, means for oscillating saidshuttle means about its axis between two limits in a plane parallel tothe direction of oscillations of said needle bar frame to normallycooperate with said needle in each lateral position to form zigzagstitches and means for selectively moving the limits of oscillatorymovement of said oscillatable shuttle about the axis thereof so thatsaid shuttle will not pass said needle when at one of its lateralpositions whereby a basting stitch will be formed by said needle andsaid shuttle means at the other lateral position.
 2. A sewing machine asclaimed in claim 1 wherein said means for moving the limits ofoscillatory movement of said oscillatable shuttle includes a connectingrod mounted at one end to a crank provided on the main drive shaft ofthe sewing machine, rotatably adjustable pin means mounted at the otherend of said connecting rod, a lever connected at one end to saidadjustable pin means for oscillation thereby, a shaft oscillatable bysaid lever, said shuttle means being operably connected to saidoscillatable shaft, said rotatably adjustable pin means having aneccentric portion connected to said lever and means for selectivelyrotating said pin means so that the eccentric portion of said pin meanswill change the limits of oscillation of said shaft.
 3. A sewing machineas claimed in claim 2 wherein said means for selectively rotating saidpin means includes means for locking said pin means in a selectedposition.
 4. A sewing machine as claimed in claim 3 wherein saidadjustable pin means includes means for manually operating said lockingmeans and for adjusting said pin means to the desired position.